Monday, February 24, 2014

Tick Bite Associated with Mammalian Meat Allergy (MMA) – Alpha-Gal and Anaphylaxis

Meat Allergy May be Caused by Tick - Photo by James Lindsey at Ecology of Commanster
Those who suffer from food allergies are often well versed on the symptoms they usually experience. Some people with food allergies have immediate symptoms of anaphylaxis, such as swelling of the face, lips, and/or throat, shortness of breath, an itchy rash or hives, and/or a dangerous drop in blood pressure. In severe cases, death can result due to an anaphylactic allergic reaction to a food. Other people with food allergies tend to experience more gastrointestinal symptoms, such as abdominal pain, vomiting, and/or diarrhea.

Allergic reactions, particularly anaphylactic reactions that can quickly become an emergency situation, typically occur rapidly, within minutes of exposure to an allergen. However, an allergy to meats such as beef, lamb, pork, or other mammals tends to occur approximately four hours after the person ingests the food, making it quite difficult to pinpoint the offending allergen. Many people with a mammalian meat allergy may experience these delayed allergic reactions and suffer for quite a while treating these mysterious allergic symptoms without a clear cause.

People identified as having a mammalian meat allergy (MMA) develop antibodies to alpha-gal (galactose-alpha-1,3-galactose), a carbohydrate found in the meat of mammals. Some people have the antibodies but have not experienced allergic reactions. Persons with MMA may also experience allergic reactions to milk products, gelatin, whey-containing protein powder, and certain medications.

Recent studies indicate that some ticks have alpha-gal in their gastrointestinal tracts. People with mammalian meat allergy often report having had at least one tick bite, leading to the theory that this allergy is vector-borne. The larvae and nymph stages of the ticks may be difficult to identify, perhaps being confused with seed ticks or chiggers. Those who live in or travel to areas with higher numbers of these ticks, such as the southeastern United States, may be at increased risk for developing MMA. Those with MMA often report a memorable tick bite that may have taken longer than normal to heal.

More studies are needed to determine additional information regarding this unusual food allergy that may be increasing. The only treatment for MMA at this point is to avoid all mammalian meats and other products that cause symptoms, such as milk. Other non-mammalian meats, such as turkey, chicken, and fish, may be safe for people with MMA to consume without resulting symptoms unless they have additional allergies. Some people with MMA may have other allergies or sensitivities to additional foods, such as those who have celiac disease.

Immediately seek emergency care if you are experiencing life-threatening allergic symptoms. Check with your healthcare provider if you suspect that you may have a meat allergy to determine any necessary testing and a safe care plan that meets your individual needs. This article is for informational purposes and should not be considered medical advice.

Additional Articles:

References:
  • "Alpha-Gal Basics" online article by Alpha-Gal Allergy Awareness web site accessed on 2/24/2014.
  • "Anaphylactic Reactions to Oligosaccharides in Red Meat: a Syndrome in Evolution," Clinical & Molecular Allergy, 2012, Vol. 10, Issue 1, p. 5-15.
  • Becker, Eve, "Ticked Off," Living Without August 2013 issue.
  • Hamsten, C. et al, "Identification of galactose-α-1,3-galactose in the gastrointestinal tract of the tick Ixodes ricinus; possible relationship with red meat allergy," Allergy, April 2013, Issue 4, p. 549-552.
  • "Ixodes ricinus" online fact sheet article last updated on 9/2009 accessed on 2/24/2014.
  • "Meat Allergy" online article by Allergist web site accessed on 2/24/2014.
  • "Rare Meat Allergy Caused by Tick Bites May be on the Rise" online article by NPR accessed on 2/24/2014.

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